For Fish, It Is Polite (and Effective) to Point

One of my friends, truly a science nerd, frequently sends me these extraordinary articles from scholarly journals. I look at them all, read as many as I can (by which I mean as many as I can get through, since they are often beyond either my understanding or patience), and occasionally I like to bring one to your attention. From a recent Nature Communications, then, the awkwardly titled but fascinating “Referential gestures in fish collaborative hunting.”

Why fascinating? The article’s three authors (two from Cambridge, the third from a university in Switzerland) document how fish, eels and octopus work collaboratively to find, communicate about, and then finally capture prey that they then share – that is, individuals of more than one species working together intentionally as a team, communicating across the barriers of their distinct biology.

(Ok, something of a joke and then again not: at a time when members of our own species are so publicly failing at collaboration, isn’t this especially cool?)

Groupers are fish capable of sudden bursts of great speed. Moray eels, because of their snake-like bodies, can shimmy into tight spaces. Wrasses have powerful, parrot-like beaks that smash open reef and corals. Combine speed with the ability to get into tight hiding spaces and then add the strength to tear open those spaces, and you’ve created a combined hunting ability far more efficient than any one of those alone. How, then, to coordinate this inter-specific behavior?

The grouper takes the lead, using two distinct behaviors to kick off and then orchestrate the collaborative hunt. First, shimmying his or her full body in front of the others while swimming in a normal, horizontal orientation, the grouper asks for and often gets the partners to follow. Then, once prey is found, the grouper moves into position above the target and shifts into a head-standing (head down, tail up) orientation, signaling with distinctive head-shaking behavior to indicate the crevice in which the meal is to be found. Enter the skinny eel, the crowbar jawed wrasse, and dinner is served.

Similar behavior is reported for a saltwater coral trout who signals much the same way to get the physical assist from octopuses in the Great Barrier Reef.

The authors report previously known examples of this sort of purposeful pointing (a.k.a. “referential gestures”) among chimpanzees and other great apes and, more recently, with ravens. Like pre-verbal human babies who point to ask for what they want, so too chimps and other primates as well as ravens use gestures to signal their desires and intentions in the obvious and often successful attempt to gain the cooperation of others. As interesting as that is for collaborative, non-verbal and purposeful communication within a group of the same species of animal, this crosses boundaries in a truly remarkable way.

So while we’ve long known than teamwork is not something unique to humans, the story here is more like that of a 6 month old human in the company of a chimpanzee and a raven, pointing at and getting something that all three of them want and can share. Now that’s an article I look forward to reading.